I'm picking up the radiator for the SA 200 Monday, and will be painting and reassembling according to the wind speed over the next couple of weeks. When I get the old gal running, I'd like to do a check on the output through the leads.
Would I do this with a helper and an amp clamp? Set it up to weld, and then weld with a helper watching an amp clamp on the lead? Is there another type of tester I should use just on the main lugs off the machine? I'm just trying to see if the output is good, and is within the range of the controls indicate. I will be using 50' leads of #1 cable on each leg. I will be using 7018 1/8" rod in the flat position, and making a dime size pool, and trying to burn thirty seconds per setting. Stinger positive.
Does this sound like a plausible idea? Other suggestions, caveats, tips, procedures or whatever appreciated.
Unless you have a DC amp clamp..you cant do it. Most ammeters using inductince to read current, are AC only. Your machine is DC only.
Put a volt meter across the leads, see what it says. Have your helper read it while welding.
Frankly..I consider the dials on most welders to be only a a way to figure out what the needle was pointing at the last time it worked good. Then I use a grease pencil to make a mark for the size/type of rod it worked well at.
Now there is "shunt ammeters" but I dont have a clue how to hook one up for your rig.
Just wire wheel some of your scrap, grab a mixture of rod, and burn it. Set it at what the dial says..then adjust up or down as needed for each rod.
You could use an automotive starting/charging current meter, which is a simple DC magnetic meter with grooves on the back for the wire. They aren't very accurate but you just place it on the lead. The one I have reads charging current to 75A with 5A graduations, or 400A starting current to 25A.
6013 or 7014 rod (and maybe 7018, haven't tried it) will weld by itself if laid flat on the work, then you could let go and read the meter.
I'd be more concerned with maximum AC line current.
I found a rather nice hall effect AC/DC clamp probe by TPI at FRy's for about $60 (plug into any DMM), and it's rated for 1,600A AC / 2,000A DC. A whole lot cheaper than the Fluke equivalent and seems to work just fine.
You could use a shunt type meter. The most common meter standard for these are 50 millivolts. You will need a meter movement and a shunt covering the maximum current you will be reading. The shunt should be placed in series with either welder lead observing the polarity from the welder, shunt and meter movement. This will be the most accurate, but a clamp on attachment to a DVM, as others have suggested, should be quite adequate.
I would use a DC shunt, as you said, and a regular multimeter set at the lowest voltage scale (2000 mV in my case).
These shunts are not very expensive.
If you know the gauge and exact length of your cables, you can short your welder through those cables and measure voltage drop, and arrive at a fairly good current number based on resistance of cable of your gauge.
You could use an automotive starting/charging current meter, which is a simple DC magnetic meter with grooves on the back for the wire. They aren't very accurate but you just place it on the lead. The one I have reads charging current to 75A with 5A graduations, or 400A starting current to 25A.
6013 or 7014 rod (and maybe 7018, haven't tried it) will weld by itself if laid flat on the work, then you could let go and read the meter.
I'd be more concerned with maximum AC line current.
This is really good advise. I would get an analog voltmeter and measure the voltage drop just across the work lead. Measure the length, look up the resistance of that size cable and calculate the current. Note the temp of the cable and correct for that for more accuracy.
That's a good idea. Voltage drop may be about 1 v olt, easily measurable with good accuracy. There are ohms per foot tables for various gauges. Attaching one
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AWG Wire Table for BARE COPPER Wire Compiled by a program written by Fr. Tom McGahee
Compiled by Fr. Tom McGahee tom snipped-for-privacy@sigmais.com Permission granted to copy freely so long as credit line above is included
AWG = American Wire Gauge size Dia-mils = Diameter in mils (1 mil = .001 inch) TPI = Turns Per Inch (Ignoring thickness of unknown insulation) Dia-mm = Diameter in millimeters (For comparison with non-USA coilers) Circ-mils = Circular Mils. (circular mils = diameter in mils squared) Ohms/Kft = Ohms Per 1,000 Feet Ft/Ohm = Feet Per Ohm Ft/Lb = Feet Per Pound Ohms/Lb = Ohms Per Pound Lb/Kft = Pounds Per 1,000 Feet NormAmps = Normal Average Amp Capacity based on 500 circular mils per Amp MaxAmps = Maximum recommended Average Amp Capacity in Open Air based on 438.489 circular mils per Amp
Actual Amp capacity of a wire depends on form factor and method of cooling! MaxAmps assumes free flow of air around wire. Do NOT exceed this maximum without cooling! Wire wrapped in a coil or without any form of cooling may over-heat at MaxAmps! Many factors govern the ACTUAL Max Amps you can pass through a wire continuously. Be careful!
Yep. Bright yellow case unit. They have a couple models that look superficially the same, two are AC only and the third is AC/DC and has the extra DC zero knob on it. It also apparently was rated something like 800A, but subsequently upgraded with stickers on the package to the
Cheap, for sure. Not as easy as an ammeter. Not very much accurate, I'd say. You have unknown accuracy in the wire guage, unknown resistance in the cable connections and in the clamps. Analog meters are hard to read precisely and are only accurate to a couple of percent.
Bob
And don't start with "The OP doesn't need more accuracy than that". I'm responding to the statement that it would be "accurate".
And a couple of percent isn't accurate enough for a stick welder?
How about the digital clamp on ammeter working with the high RF environment of an arc?
Who said the measurement would be made beyond the connectors? You?
Four place resistance figures for the cable aren't accurate enough? Its easy to see an analog meter and integrate out all the variations with an unstable DC arc. Seems you have never tried to measure the current of a DC welder.
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